1. Field
The following description relates to a resonator and a resonating method.
2. Description of Related Art
LC resonators are frequently used in a wireless power transmission field. A resonant frequency of an LC resonator is determined and fixed based on an inductance of an inductor and a capacitance of a capacitor.
An initially set resonant frequency varies (or drifts) due to various factors between a transmission end (transmitter) and a reception end (receiver). Accordingly, to properly tune the resonant frequency for each situation, the transmission end or the reception end needs to calibrate the resonant frequency. In addition, in the wireless power transmission field, to transmit power through resonance matching it may be necessary to adjust the resonance for either of the transmission end or the reception end.
A typical frequency calibration approach includes directly or indirectly changing the effective value of at least one of an individual inductor and capacitor used in the corresponding resonator. For example, the inductor of the resonator may be a long coil where initially only an intermediate portion of the long coil is used to generate the resonance. When a resonant frequency of the resonator needs to be changed, the inductance is adjusted by changing the extent of the long coil used as the intermediate portion. In the same manner, to have different capacitor values available, a capacitor having several values must be available, or multiple different capacitors of different values must be available. The different capacitances would be switched in or out of the resonance circuit, similar to the adjusting of the extent of the inductor coil that is used.
In other words, to calibrate a frequency in a typical LC resonator, a resonant frequency is changed using one or more inductors and capacitors that can be selectively switched into the resonance circuit to obtain the desired resonant frequency. The changing of the resonant frequency indicates selecting of a desired resonant frequency from discontinuous resonant frequencies. Thus, to have the capability to select various resonant frequencies, the number of required devices, for example, respective switched in devices increases proportionally with the desired various available resonant frequencies.